A computer network's basic functionality is determined by the configuration of the network devices present in the network. Network devices include routers, network switches, servers, firewalls, and virtual private networks.
A router is a network gateway that joins two or more IP networks and switches packets between the networks. A network administrator can implement a high-level corporate routing policy by configuring the settings of each router in the network, including setting static routes, one or more dynamic routing protocols, suppressing dynamic routing updates on a per-interface basis, and setting routing preferences.
A network switch is a multi-port network bridge, which is generally capable of supporting multiple media types. A network bridge forwards datagrams (packets) according to media type and address (e.g., Ethernet). A network administrator can configure a network switch in much the same way as configuring a router.
A server is a host (computer) that offers one or more services used by all the other networked computers to simplify the operations of the network, such as DNS (domain name service), mail (electronic mail), and web services. A network administrator can configure the software for the particular service and can also configure the host itself (e.g., access control to the computer via TCP wrapper configuration).
A firewall is a network gateway that filters packets and separates a proprietary corporate network, such as an intranet, from a public network, such as the Internet. Most of today's firewalls are configured by means of a rule-base. A network administrator can implement a high-level corporate security policy by creating a low-level rule-base for each firewall interface in the corporate network.
A virtual private network (VPN) is a network device that secures the privacy of corporate data outside the perimeter of the corporate network. A network administrator can configure VPN devices so that corporate data sent over the public Internet (e.g., from the corporate headquarters to a remote company site) is adequately secured. This typically involves configuring settings for cryptographic key exchanges, choosing the appropriate encryption for sending data (e.g., IP packets) according to the destination, etc.
A network topology is a formal description (including IP-addresses, device description, etc.) of the network devices interconnecting the sub-networks and hosts in the network.
A network policy is a formal description of the intended capabilities and properties of the network hosts in the network.
A configuration file contains configuration data for a single network device, such as a router, firewall, or server.
A network configuration model is a data model for representing a global configuration of the network, which uses the configuration files as building blocks. A network configuration store is a device for storage of network configuration models.
A network administrator, or a group of administrators in a larger enterprise, is typically responsible for configuring all the network devices in a network, in such a way that the network devices can cooperatively enforce a corporate network policy. Any error in the configuration file of a single network device can invalidate the enforcement of the network policy. Furthermore, errors in the configuration files can go undetected for a long time. For example, a router configuration error can cause IP traffic from the Internet, which is destined for a number of hosts (computers) within the corporate network (enterprise), to be lost. Traditional network management software will not generate any alerts. Since all the routers are up and running, the routers will not generate an event to which the management software would react.
As apparent from the above-described deficiencies associated with the manual configuration of network devices, a need exists for a method and apparatus for analyzing a configuration file of each network device in a corporate (enterprise) network, matching the results against a corporate network policy, and generating reports for network administrators indicating any violations in the collective network configuration against the corporate network policy.